TWI409099B - Baffle assembly module for vertical staged polymerization reactors - Google Patents

Abstract

The present invention provides an assembly for use in vertical, gravity flow driven polymerization reactors for combinations of high viscosity, high throughput, and shallow polymer depths. The baffle assembly module of the invention includes a support structure having a plurality of side openings. The side openings allow the escape of vapor liberated from the polymeric melt. The assembly further includes a feed splitter followed by two or more vertically arranged rows of baffle plates with the feed splitter and baffles sequentially positioned in the support structure. The plurality of parallel baffles in a row are angled such that when a polymeric melt contacts a given baffle the polymeric melt moves in a downward direction under the force of gravity. The arrangement of the rows is such that each row (except the lowest row) transfers the polymeric melt to a lower vertically adjacent row until reaching the last row of baffles in the module. According to the vertical arrangement of the components in the baffle assembly module and by stacking additional baffle assembly modules if needed within the reactor, the polymeric melt cascades down the vertical length of the reaction vessel interior. The present invention also provides a polymerization reactor that incorporates the assembly of the invention and a method of increasing the degree of polymerization of a polymer melt by using the assembly of the invention.

Description

Baffle assembly module for vertical polymerization reactor

This invention relates to an apparatus for producing polycondensation products such as linear polyesters and copolyesters. More specifically, the present invention relates to an improved reactor internal component design for a vertical orientation polymerization reactor.

The method for producing a polymeric material such as a polyester and a copolyester via a polycondensation reaction involves the release of by-products when the polymeric functional groups of the molecules react with one another to produce molecules of longer molecular chains. Typically, such released by-product molecules must be extracted from the reaction mixture to drive the molecular accumulation of the polymer. If the by-product compound is not removed, the chemical equilibrium will inhibit the length of the polymer chain formed. In many polycondensation reaction systems, a preferred method for extracting the released by-products is to evaporate by-products out of the reaction mixture.

A variety of reactor designs and multi-step reaction systems have been designed and operated to facilitate the evaporation of by-products and related production of polycondensation materials. The most economical design for these polycondensation reactions (at least for the production of low molecular weight to medium molecular weight polymeric materials) is a series of stirred tank reactors. A large amount of material can be produced in such reactor systems using mechanical agitation, thermosiphon reboilers and/or simple bubble agitation to enhance heat transfer and liquid-gas surface area renewal. Unfortunately, as the degree of polymerization ("DP") increases, the viscosity of the polymer solution increases significantly. Thus, due to the practical limitations of the agitator design, the high viscosity of such materials greatly reduces the ability to renew the liquid-gas surface and thus the mass transfer efficiency of the stirred tank reactor.

In addition to the features set forth above, other operational parameters may be limited in the polycondensation process. For example, higher temperatures are required to increase the kinetics of the reaction and the volatility of the by-products of the reaction. The higher volatility of by-products reduces the concentration of by-products in the reaction mixture, thereby promoting the polymerization. However, the temperature at which the polymeric substance is increasingly sensitive to the temperature sensitivity of the degradation reaction is used as a means to promote the degree of polymerization. Similarly, the volatility of by-products can be further increased by using low operating pressures. However, the use of very low operating pressures is limited by the cost of achieving low operating pressures and the reactor vapor space required to prevent polymer entrainment into the vacuum source. Furthermore, the depth of the polymerization tank in the low pressure polycondensation reactor can inhibit the efficient use of the reactor. In particular, too deep a reaction mixture increases the diffusion and convection paths that volatile by-products must travel before they escape. In addition, the deeper portion of the cell experiences a greater hydrostatic pressure as the depth of the polymerization cell increases. The higher partial pressure within the liquid inhibits the formation of by-product bubbles that hinder the release of by-products and thus hinder the efficient use of the reaction volume for promoting polymerization.

For the reasons stated above, increasing the degree of polymerization requires replacing the simple stirred tank reactor with specialized reaction equipment. The specialized device must overcome one or more of the above operational limitations to achieve the desired degree of polymerization. There are currently two basic methods for enhancing liquid-gas surface renewal, which are best described as dynamic methods and static methods.

The first method may be referred to as a dynamic method because it involves the use of mobile mechanisms to enhance liquid-vapor surface renewal. As noted above, enhanced liquid-gas surface renewal promotes by-product release. In dynamic methods a seal is required around the axis of rotation or through the shaft of the reactor wall. These seals must be maintained to prevent air from leaking into the reactor. Also in the dynamic method, as the container size and product viscosity increase, the size of the mechanical components must be increased to handle the increase in load. The second method can be referred to as a static method because it does not use a mobile device to update the liquid-vapor surface. The latter method uses gravity combined with vertical descent to create a polymeric film. Typically, the polymeric films flow between the trays during vertical descent. By enhancing the release of by-products, the polymeric film is driven in combination with the shearing and surface switching action produced by the vertically falling film.

Prior art patents that disclose the use of gravity in combination with vertical descent include: U.S. Patent Nos. 5,464,590 (the '590 patent), 5,466,419 (the '419 patent), 4,196,168 (the '168 patent), 3,841,836 (the '836 patent) ), No. 3,250,747 (the '747 patent) and 2,645,607 (the '607 patent). Early tray designs used vertically spaced discs (full circles combined with hollow circles, and segmented circles) that utilized most of the cross-sectional area of the container. These disk reactors use a large portion of the horizontal cross section of the pressure vessel to hold the liquid. In some designs, the disc is followed by a hollow disc, thus forming a circular-and-annular arrangement. Thus as the polymer flows from the tray to the tray, it flows over the rounded edges. Thus, the released gaseous by-product flows through the circular and annular openings. In other designs, the trays are segmented to provide a straight edge for the polymer to flow over the straight edge before dropping onto the next tray. The segmented tray design also provides an open area between the straight edge of the polymer flow and the wall of the vessel through which the gaseous byproduct can flow. For both designs, however, by-products from the evaporation of the tray were forced to flow through the same space as the polymer solution. To solve this problem, the disc diameter is made slightly smaller than the diameter of the reaction vessel. The resulting annulus is used to allow vapor transport to escape each tray and travel along a path outside the path of polymer flow to the vapor discharge nozzle of the reaction vessel. One disadvantage of this simple circular tray design is the presence of very slow moving or stagnant areas on the trays. The polymers in these stagnant areas tend to over-fire, become too viscous, cross-link and/or degrade, and the results slowly solidify. The end result is an effective reaction volume loss.

The next generation of designers changed the shape of the tray from a circle to another geometry. It eliminates the dead zone that cannot be effectively used as the reaction volume. Since these dead zones are regions that result in high levels of degradation products due to excessive calcination of the polymer, the elimination of dead zones also improves product quality. Unfortunately, such non-annular trays do not increase the effective use of the cross-sectional area of the cylindrical pressure vessel.

The basis of the more recent invention of the '590 patent and the '419 patent is a hollow disc which more effectively utilizes the cross-sectional area of the cylindrical pressure vessel while providing a polymer solution flow path which causes the liquid to die. The zone area is minimized and prevents slotting. The end result is an approximately 40% increase in tray area available for liquid retention compared to non-circular trays. The central opening of the tray provides a chimney through which steam by-products are removed.

However, as stated above, the thickness of the polymerization cell also inhibits the efficient use of the reaction vessel at low operating pressures. At a given operating pressure (vacuum level), the negative effect of the deeper polymer thickness increases in proportion to the degree of polymerization. This is attributed to a decrease in the chemical equilibrium driving force of the polymerization reaction when the concentration of the polymer end groups is decreased by the growth of the polymer chain. Therefore, in order to obtain acceptable results, the mechanism for releasing polycondensation by-products from the polymer solution must be further enhanced. This is necessary at a higher degree of polymerization so that a sufficiently low content of by-products remains in the solution, thereby allowing the polymerization to proceed efficiently. However, another important factor is that when the polymerization proceeds to a higher degree of polymerization, the viscosity substantially increases.

At sufficiently high viscosities, the tray design using substantially horizontal trays does not achieve the desired combination of high polymer yield and shallow polymer depth. By allowing the polymer to flow down the inclined tray, Lewis et al., in the design of Patent '168, achieved some degree of control over the depth of the polymer. As the polymer polymerizes along its course, increasing the slope of the continuous tray resolves the desired increased viscosity of the polymer. For polymer systems having higher yields, even higher viscosity and/or shallower operating depths, the inventions claimed in the '168 patent are extensions of their inclined tray designs.

The patent '168 design (top-and-groove tray) also achieves some degree of control over polymer depth by splitting the polymer stream into two identical streams, one of which is mirrored by another flow path. The two streams traverse from the top of the reactor to the bottom on a tilting tray. The patent '168 design innovation for simple tilt trays is to reduce the volume of reaction vessels required to close the trays in a vacuum environment. By splitting the polymer stream, the tray achieves the desired slope and thus the vertical dimension (vertical drop) required to achieve the desired polymer depth is reduced. The top-and-slot configuration cuts the horizontal length of the tray through which each half of the polymer stream must traverse before dropping into the next tray. Because each half of the polymer stream traverses a half horizontal distance, the residence time of each semi-polymer is approximately equal to the residence time of a simple tilting tray when a lower total vertical height is used.

As productivity increases, the top-and-slot design concept can be extended by splitting the polymer stream into more identical streams (typically in binary mode - two, four, eight...). Thus, as the size of the container is increased to accommodate the polymer yield, the volume of the reaction vessel is maintained to be fully utilized.

However, even for the top-and-slot tray design of Lewis, the use of the reaction vessel volume is achieved when the desired degree of polymerization is pushed higher and/or the operating window for mass delivery versus residence time is reduced to achieve better quality. cut back. When the target degree of polymerization is pushed higher, the viscosity of the polymer increases. Therefore, to maintain the same polymer depth requirements, a steeper tray slope is required. Similarly, if the mass transport is increased by targeting shallow polymer depths, a steeper tray is required. At some point, the slope becomes substantially vertical (the slope is greater than 60° from horizontal) and the slightly thinner depth of a given combination of yield and viscosity cannot be achieved by further changing the slope. In this region of high throughput, shallow depth of target, and high viscosity, the baffle assembly module of the present invention described herein increases the number of polymer sheets in a cross-sectional area of a given reaction vessel, thereby achieving high throughput and Better quality delivery.

Therefore, there is a need for an improved tray design for a polycondensation reactor that utilizes the space in a vertical flow reactor driven by gravity flow to combine high viscosity, high yield, and shallow polymer. depth.

The present invention overcomes the prior art by providing a vertical polymerization reactor for gravity flow driven in an embodiment to combine a high viscosity, high throughput and static internal components of a polymer solution film. One or more questions. The present invention also uses gravity and vertical descent methods to achieve an early design enhancement of the desired degree of polymerization. Such an earlier design is disclosed in U.S. Patent Nos. 5,464,590 (Patent '590), 5,466,419 (Patent '419), 4,196,168 (patent '168), 3,841,836 (patent '836), 3,250,747 (patent' 747) and 2,645,607 (patent '607). The entire disclosures of these patents are hereby incorporated by reference. By virtue of the novel configuration of the assembly comprising the baffle assembly module, the present invention provides an increased surface area on which the liquid contacts the atmosphere of the reactor while still obtaining sufficient liquid for the polymerization to take place. Keep time. The baffle assembly module of the present invention includes a fixed feed splitter and a fixed array of baffles or trays mounted in a support structure. The feed splitter is any device that subdivides the flowing polymer stream into two or more separate flow streams, resulting in an increase in the number of free surfaces. By dividing the polymer solution, it can be more uniformly applied to the array of baffles located below it. Typically, the baffles (tray) in the array are arranged in columns, with the baffles being at a constant elevation (i.e., height) in the column.

The baffle array provides a solid surface on which the polymer stream is from the feed splitter stream. The baffles (tray) are typically oriented at least 10 degrees from the horizontal plane. The baffle row can be formed by mounting a plurality of horizontally spaced parallel plates at equal elevations. For this array, the linear or normal spacing between adjacent baffles in a column is preferably constant.

Two or more rows of baffles (tray) are vertically arranged in the baffle assembly module. The vertically aligned baffle columns in the baffle assembly module typically have the highest positioning column, the lowest positioning column, and one or more intermediate positioning columns as desired. Each column then includes one or more baffles positioned to move the polymer solution in a downward direction under the force of gravity as the polymer solution contacts a baffle. In addition, the baffles in each column are arranged in a parallel manner. The baffle columns in the baffle assembly module are arranged such that each column (except the lowest column) transports the polymer solution to a lower vertically adjacent subsequent baffle row. According to the vertical arrangement of the components in the baffle assembly module and by stacking additional baffle assembly modules (if required in the reactor), the polymer solution flows down the waterfall along the vertical length of the interior of the reaction vessel .

The reaction vessel provides a means for controlling the pressure and temperature in the space surrounding the baffle assembly module. The baffle assembly modules are mounted in a container to provide retention of the polymer solution thereby increasing the residence time of the liquid in the reactor and increasing its exposure to the reaction conditions. Requiring the liquid residence time allows for sufficient time to allow the polymerization kinetics to catch up with the enhanced by-product release rate achieved by increasing the liquid-gas surface area and enhancing its renewal. This design not only provides more free surface area for the polymer solution, it also provides more parallel flow paths to reduce the depth of the polymer on the baffle.

The presence of a feed splitter at the top of the baffle assembly module facilitates the change in the number or orientation of baffles (tray) from one module to a subsequent lower module.

The presently preferred compositions or examples and methods of the present invention will now be described in detail.

In one embodiment of the invention, an assembly suitable for placement in a reactor for polymerizing a polymer solution is provided. Referring to Figures 1a, 1b, 2a and 2b, the baffle assembly module 10 is comprised of a fixed feed splitter and a fixed baffle mounted in a support structure 12. The feed splitter and the baffles are fixed because they have no moving parts and they do not move during operation.

The baffle assembly module 10 includes a baffle row 24 that is the highest vertical alignment column and another baffle row 26 that is the lowest vertical alignment column. The baffle assembly module 10 will also include one or more intermediate positioning columns 28, 30, 32, 34, as desired. Each of the vertically aligned baffle rows 24-34 includes a plurality of baffles 36, 38, 40, 42, 44, 46. Typically each column has from about 8 to about 60 baffles. Moreover, each of the plurality of baffles 36-46 is angled and biased in the same direction such that when the polymer solution contacts a baffle of the plurality of baffles 36-46, the polymer solution is Move in the downward direction under the action of gravity. In this case, biasing in the same direction means that for each given column, each baffle of the plurality of baffles directs the flow of the polymer solution in the same direction, that is, when the baffle is viewed from the end, The flow of each baffle in the column is from left to right or from right to left. Or, as specified, the baffles in each column are substantially parallel or have no relative angles greater than 90 degrees between the two baffles in a column. Moreover, in addition to the lowest positioning column, each of the vertically aligned columns 24-34 transports the polymer solution to a lower vertical adjacent column. In addition, there is a consistent clearing between the baffles in a column. As used herein, "consistent removal" means that the baffles are separated by a sufficient distance to prevent the polymer solution 46 from bridging the gap between adjacent baffles in a column.

The feed splitter is any device that can be used to evenly separate the polymer stream onto the baffle. A feed splitter can be formed from a plate by adding appropriately positioned openings. Likewise, an array of rods, rods, tubes, half tubes, and angles can be easily aligned to form a feed splitter.

The baffle assembly module 10 includes a feed splitter box that uses a perforated plate split flow. After flowing through the split rafts 14, 16, 18 and 20, the polymer solution strikes the additional splitters 48, 50, 52, 54. When the number of shunts 14, 16, 18, and 20 is equal to one-half the number of baffles in a column, such additional shunts 48, 50, 52, and 54 are required. The splitters 48, 50, 52 and 54 are shown as being made up of half circular plates (half tubes). However, it should be noted that other shapes, such as curved plates (meaning "angles"), can also be used. Support structure 12 generally includes a first pair of opposing sides 60, 62 and a second pair of opposing sides 64, 66. A baffle row 24-34 is located between the first pair of opposing sides 60, 62 and each baffle of the baffle rows 24-34 is disposed between the second pair of opposing sides 64, 66. Moreover, the second pair of opposing sides 64, 66 includes a plurality of openings 22 adapted to allow vapors released from the polymer solution to escape.

Referring to Figure 3, a schematic diagram illustrating the flow of a polymer solution in a baffle assembly module of the present invention is provided. The polymer solution 70 enters via the crucible 72 and is introduced at the top of the baffle assembly module 10. The polymer flows down onto the plate 74. The polymer solution 70 then flows through the shunts 14, 16, 18 and 20 located in the plate 74. The flow through the branches 、 14, 16, 18, 20 is used to divide the flow of the polymer solution 70. The polymer solution 70 then impinges on the splitters 48, 50, 52, 54 which further divide the flow into flow streams 76, 78, 80 flowing onto each of the baffles 36 of the uppermost column 24, 82, 84, 86, 88, 90. The polymer solution 70 then continues to flow down the baffle 36 and then to the baffle 38, with each of the flow streams 76-90 flowing to the nearest baffle of the baffle 38. This process is repeated for each column of baffles until the lowest baffle row 46 is reached. The baffles 36-46 in each of the columns 24-34 are at an angle a, as measured from the horizontal plane when viewed from the side. As measured from the water level, α is typically from about 10 degrees to about 80 degrees. Furthermore, a given baffle row will direct the polymer solution 70 downward from left to right or from right to left when viewed from the side. In addition, in each column, the direction from left to right or from right to left will change between adjacent columns. Another valuable aspect of this baffle (tray) design is that it maintains the polymer turnover of the top-and-groove tray design. As the polymer flows from the baffle to the baffle, both sides of the polymer stream flowing in layers are alternately exposed to the gas-liquid interface. The polymer on top of the polymer stream on a baffle is at the bottom of the cell opposite the bottom of the next baffle, and vice versa, the polymer already at the bottom of the stream is at the top of the flow stream and exposed to the next block Steam on the board. However, each of the given columns 24-34 will direct the flow in the same direction. Thus, each of the baffles of a given column of columns 24-34 is generally substantially parallel. Non-parallel baffles are within the scope of the invention as long as the guiding directions of all of the baffles in a row are the same.

The relationship between the thickness of the flow stream 76-90 and the geometry and fluid physics of the baffle or tray approximates Equation I: (3 Fμ) / (ρgd ³ ) = WN sin(α) I where F is the polymer passing through the reactor The total mass flow, g is the gravitational acceleration, d is the thickness of the polymer solution as shown in Figure 3a, μ is the polymer solution dynamic viscosity, ρ is the polymer solution density, and W is the baffle width, N Is the number of baffles in a row, and a is the angle that defines the bevel of the baffle with respect to the horizontal plane. The angle a is typically from about 10 degrees to about 80 degrees with respect to the horizontal plane.

Referring to Figure 4, a chart illustrating the layout of the baffle is provided. For a given alpha, d ₁ is the vertical distance between each baffle in a single column, d ₂ is the distance of the horizontal deviation between the vertically adjacent columns of the baffle, and d ₃ is the vertical between adjacent columns of the baffle Deviation or gap, d ₄ is the horizontal span of each baffle and d ₅ is the vertical drop of each baffle. The distance d ₁ is typically from about 1 inch to about 10 inches. In other variations, d ₁ is typically from about 2 inches to about 8 inches. In still other variations, d ₁ is from about 4 inches to about 5 inches. Typically, the distance between each of the plurality of baffles is such that when the polymer solution flows through the baffle assembly module during steady state operation, the thickness of the polymer solution is the distance between adjacent baffles in a column. At least 10%. Typically, d ₂ is from about 1 inch to about 5 inches, d ₃ is from about 0 inches to about 6 inches, d ₄ is from about 4 inches to about 48 inches, and d ₅ is about 4 inches to About 48 miles. In other variations, d ₂ is from about 2 inches to about 4 inches, d ₃ is from about 1 inch to about 3 inches, d ₄ is from about 6 inches to about 12 inches, and d ₅ is about 8 The British to about 24 miles. In other variations, during steady state operation, the polymer solution thickness is at least 20% of the distance between adjacent baffles in a column. In still other variations, during steady state operation, the polymer solution thickness is at least 40% of the distance between adjacent baffles in a column.

In a variation of the invention, one or more baffle extensions are attached to the bottom edge of each baffle that transports the polymer solution to a subsequent vertically positioned baffle. Referring to Figures 5a-f, a schematic diagram illustrating the effect of baffle extensions on polymer solution flow is provided. In Figure 5a, baffle 100 is designed to deliver polymer solution 102 to baffle 104. However, under certain conditions without any baffle extensions on the end of the baffle 100, there is a potential for the polymer solution 102 to bypass the baffle 104. This is due to the fact that the polymer flows down a baffle with the liquid on the exposed top surface moving faster than the polymer flowing along the bottom formed by the baffle. Thus, as the polymer stream reaches the bottom of the baffle, it tends to bend back toward the bottom of the baffle from which the polymer exits. Usually, this does not cause a lot of horizontal movement. However, because the lower baffle slopes at a steep angle in the same direction, the polymer can strike the next lower baffle along the baffle a distance or completely across the baffle. In Figure 5b, the baffle 100 includes one or more baffle extensions 106 that, as illustrated, help direct flow onto the baffle 104. Thus, a baffle extension consisting of a rod or finger extending from the bottom edge of the baffle (tray) is a reinforcement for this invention. The distance between the rods or fingers depends on the desired polymer viscosity and flow rate. The fingers extend vertically downward from the baffle to which they are attached, but stop at a desired height that is shorter than the polymer depth on the next lower baffle. With such fingers, the polymer from a baffle is directed to the subsequent baffles to make more use of the subsequent baffle surface area.

Referring to Figure 5c, another non-optimal polymer solution flow that can occur without a baffle extension is illustrated. In this case, it is observed that the polymer solution 102 flows in a discontinuous manner ("snowball") in the downwardly advancing baffle 100 and thus flows from the baffle 100 to the baffle 104. At the location where the falling material 102 contacts the baffle 104, the substance has some fold at its top. This degree of folding combined with the slope of the baffle 104 can result in a discontinuous flow as shown. Figure 5d illustrates how the baffle extension 106 remedies this situation by reducing the extent to which the fold occurs.

Referring to Figure 5e, an end view of the polymer solution 102 flowing from the baffle 100 is provided. In the absence of a baffle extension, the width of the falling film decreases as the polymer solution 102 is pulled toward the middle of the baffle 100. As shown in Figure 5f, the baffle extension 106 tends to mitigate this effect. Typically the or such baffle extensions comprise a plurality of rod-like projections extending from the bottom edge of each baffle.

In another embodiment of the invention, a polymerization reactor utilizing one or more of the baffle assembly modules set forth above is provided. Referring to Figures 1 and 6, the polymerization reactor 120 includes a baffle assembly module 10 and a vertically disposed containment 122. The polymer solution inlet 124 is attached to the top 126 of the outer shell 122 and the attached polymer solution outlet 128 is attached adjacent the bottom 130 of the outer casing 122. In addition, polymerization reactor 120 also includes a vapor outlet 132 that is attached to outer casing 122. Finally, the polymerization reactor 120 includes a baffle assembly module 10 that, as set forth above, receives the polymer solution from the polymer solution inlet and transports the polymer solution to the polymer solution outlet. 128. In another variation of this embodiment, an additional baffle assembly may be present in the polymerization reactor 120. These additional baffle assemblies can be placed side by side with the baffle assembly module 10 and/or stacked under the baffle assembly 10. The polymerization reactor 120 also includes a heater (not shown) for maintaining the polymer solution in a fluid state and a vacuum pump (not shown) for reducing the pressure in the polymerization reactor. The vacuum pump typically acts through the steam outlet 132. In particular, the baffle assembly module 10 includes two or more rows of vertically aligned baffle rows 24-34. The vertically aligned columns have a highest positioning column 24, a lowest positioning column 26, and optionally one or more columns of intermediate positioning columns 28-34. In addition, each of the columns of vertically aligned rows 24-34 includes a plurality of baffles that are angled such that the polymer solution is in gravity when the polymer solution contacts one of the plurality of baffles Move in the downward direction under the action. Finally, in addition to the lowest positioning column 26, each of the columns is adapted to transport the polymer solution to a lower vertical adjacent column.

In yet another embodiment of the present invention, a method of increasing the degree of polymerization in a polymer solution using the baffle assembly module set forth above is provided. The method of the present invention involves introducing a polymer solution into the baffle assembly module at a sufficient temperature and pressure. The details of the assembly are stated above. The method of this embodiment comprises splitting the polymer solution stream before the highest positioning column of the baffle contacts the polymer solution. Next, the optional baffle intermediate column is in contact with the polymer solution. Finally, the lowest positioning column of the baffle is in contact with the polymer solution. After the polymer solution passes through the lowest positioning column of the baffle, the baffle assembly module flows out. The polymer solution removed from the baffle assembly module advantageously has a higher degree of polymerization than when the polymer solution is introduced into the assembly. In a variation of this embodiment, the reaction temperature is from about 250 ° C to about 320 ° C and the reaction pressure is from about 0.2 Torr to about 30 Torr.

To achieve effective space utilization, the horizontal spacing within a baffle row can be adapted to the viscosity of the liquid (i.e., polymer solution). Thus, as the viscosity increases from the top to the bottom of the reactor, the minimum horizontal spacing between adjacent baffles in a column can be increased. As a result, the number of baffles in a row can be less for subsequent lower baffle assembly modules. Therefore, the feed splitter design used in each module must account for any change in the number of baffles in a column. Similarly, the design of the feed splitter in each module facilitates a change in the orientation of the baffle, such as rotating the baffle in the continuous module 90 degrees around the centerline of the reactor.

It should also be appreciated that many baffle assembly modules can be stacked to provide a longer flow path for the polymer solution. Although this example illustrates the use of a single module assembly, any number of module assemblies can be utilized. The actual number of module assemblies required depends on many factors.

While the embodiments of the present invention have been illustrated and described, it is not intended to Rather, the words used in the specification are for the purpose of description and description

10. . . Baffle assembly module

12. . . Support structure

14, 16, 18, 20. . . Diversion

twenty two. . . Opening

twenty four. . . Top positioning column

26. . . Lowest positioning column

28, 30, 32, 34. . . Intermediate positioning column

36, 38, 40, 42, 44, 46. . . Baffle

48, 50, 52, 54. . . Splitter

60, 62. . . First pair of opposite sides

64, 66. . . Second pair of opposite sides

70. . . Polymer solution

72. . . port

74. . . board

76, 78, 80, 82, 84, 86, 88, 90. . . Flow current

100, 104. . . Baffle

102. . . Polymer melt

106. . . Baffle extension

120. . . Polymerization reactor

122. . . shell

124. . . Entrance

126. . . Top of the casing

128. . . Export

130. . . Bottom of the casing

132. . . Steam outlet

1a is a cross-sectional view of an embodiment of a baffle assembly module of the present invention showing a feed splitter and a subsequent parallel baffle array in a support structure; FIG. 1b is a baffle assembly of the present invention; FIG. 2a is a perspective view of the baffle assembly module of the present invention; FIG. 2b is a perspective view of the baffle assembly module of the present invention, wherein one wall of the support structure Removed to expose the internal baffle configuration; Figure 3a is a side view of the baffle zone where the polymer solution flows over the baffle zone; Figure 3b illustrates the polymer solution flowing through the feed splitter and flowing to Schematic diagram of the subsequent baffle in the assembly of the present invention; FIG. 4 is a graph showing the spatial relationship between the baffles used in the baffle assembly module of the present invention; FIG. 5a shows that the polymer solution flow may miss one An illustration of the mechanism of the baffle; Figure 5b is an illustration showing the use of a baffle extension to prevent the polymer stream from missing a baffle (as shown in Figure 5a); Figure 5c is a diagram showing the discontinuous polymer dissolution on a baffle An illustration of body flow; Figure 5d shows the use of baffle extensions to prevent discontinuous polymer flow ( Figure 5e is an explanatory view showing a decrease in the width of the polymer sheet when the polymer sheet falls between the baffles; Figure 5f is a view showing the use of the baffle extension to reduce the width of the polymer sheet An illustration of a minimized (as shown in Figure 5e); Figure 6a is a side view of a polymerization reactor comprising a vessel enclosing a baffle assembly module of the present invention; and Figure 6b is a baffle assembly mold incorporating the present invention A top view of a set of polymerization reactors showing a polymer inlet nozzle and a polymer outlet nozzle and a nozzle for removing gas.

14, 16, 18, 20. . . Diversion

36, 38, 40, 42, 44, 46. . . Baffle

48, 50, 52, 54. . . Splitter

60, 62. . . Opposite side

Claims (25)

A module assembly for a gravity flow driven vertical polymerization reactor for polymerizing a polymer solution having a high viscosity, the assembly comprising: a support structure having a suitable a plurality of side openings from which the vapor released by the polymer solution escapes; and a feed splitter for subdividing the polymer stream; and two or more columns vertically aligned in the support structure a row of columns, the two or more columns of vertically aligned columns having a highest positioning column, a lowest positioning column, and optionally one or more columns of intermediate positioning columns, wherein the two or more columns are vertically aligned Each of the columns includes a plurality of baffles that are angled and biased in the same direction such that the polymer solution is in contact when the polymer solution contacts one of the plurality of baffles Moving in a downward direction by gravity, and wherein each of the two or more columns of vertically aligned columns is adapted to transport the polymer solution to a lower vertical adjacent column in addition to the lowest positioning column . The assembly of claim 1, wherein each of the two or more columns of vertically positioned columns comprises a plurality of substantially parallel baffles. The assembly of claim 1, wherein the distance between each of the plurality of baffles in a single column is such that the polymer dissolves when the polymer solution flows through the assembly during steady state operation The body thickness is at least 10% of the distance between the horizontally adjacent baffles. Such as the assembly of claim 1, wherein the plural is measured as measured from a horizontal plane Each baffle of each of the baffles is positioned at an angle of from about 10 degrees to about 80 degrees. The assembly of claim 1 wherein each of the two or more columns of vertically aligned columns comprises from about 8 to about 60 baffles. The assembly of claim 1, wherein the vertically aligned columns comprise a plurality of baffles, wherein each baffle of the plurality of baffles in a column is separated by a minimum distance of from about 1 inch to about 10 inches. The assembly of claim 1, wherein the vertically aligned columns comprise a plurality of baffles, wherein each baffle of the plurality of baffles in a column is separated by a minimum distance of from about 2 inches to about 8 inches. The assembly of claim 1, wherein each of the two or more columns of vertically aligned columns is adapted to transport the polymer solution to a lower vertical adjacent column in addition to the lowest positioning column Each baffle is caused to transport the polymer solution to a nearest downward vertical positioning baffle. The assembly of claim 8 wherein each of the baffles transporting the polymer solution to a nearest downward vertical positioning baffle further comprises one or more baffle extensions. The assembly of claim 9, wherein the one or more baffle extensions comprise a plurality of rod-like protrusions extending from a bottom edge of one of the baffles, the protrusions being adapted to transport the polymer solution to a nearest Position the bezel vertically downwards. The assembly of claim 1, wherein the support structure comprises a first pair of opposite sides and a second pair of opposite sides, wherein the two or more columns of vertically aligned baffle columns are disposed on the opposite side of the first pair Each baffle between the plurality of baffles is disposed between the opposite sides of the second pair. The assembly of claim 11, wherein the second pair of opposite side supports of the support structure The plurality of openings adapted to allow vapors released from the polymer solution to escape. The assembly of claim 12, wherein the plurality of openings adapted to allow vapor released from the polymer solution to escape are adjacent to a gap between two adjacent baffles of the plurality of baffles. An assembly according to claim 1, further comprising one or more polymer solution splitters adapted to split the polymer dissolved from the feed splitter or from one or more polymer inlets body. A polymerization reactor comprising an assembly as claimed in claim 1 placed in a vertically disposed containment. A method of increasing the degree of polymerization in a polymer solution, the method comprising: a) introducing the polymer solution into an assembly at a temperature and pressure sufficient to increase the degree of polymerization of the polymer solution, The assembly comprises: a feed splitter and two or more columns of vertically arranged baffles, the two or more columns of vertically arranged columns having a highest positioning baffle row, a lowest positioning baffle column and One or more optional intermediate positioning baffle columns, wherein each of the two or more columns of vertically aligned columns includes a plurality of baffles that are angled and biased in the same direction So that when the polymer solution contacts one of the plurality of baffles, the polymer solution moves in a downward direction under the force of gravity, and wherein the two columns are removed in addition to the lowest positioning column Each of the two or more columns arranged vertically is adapted to transport the polymer solution to a lower vertical adjacent column; b) contacting the highest positioning baffle column with the polymer solution; c) contacting the optional intermediate baffle column with the polymer solution; d) placing the lowest positioning baffle column with the polymer Contacting the solution; and e) removing the polymer solution from the assembly, wherein the polymer solution removed from the assembly has a higher polymerization than when the polymer solution is introduced into the assembly degree. The method of claim 16, wherein the temperature is from about 250 °C to about 320 °C. The method of claim 16, wherein the pressure is from about 0.2 Torr to about 30 Torr. The method of claim 16, wherein each of the two or more columns of vertically positioned columns comprises a plurality of substantially parallel baffles. The method of claim 16, wherein the distance between each of the plurality of baffles is such that the polymer solution is horizontally adjacent when the polymer solution flows through the assembly during steady state operation. At least 10% of the distance between the baffles. The method of claim 16, wherein each of the two or more columns of vertically aligned columns is adapted to transport the polymer solution to a lower vertical adjacent column, in addition to the lowest positioning column, such that Each baffle transports the polymer solution to a nearest downward vertical positioning baffle. The method of claim 21, wherein each of the baffles transporting the polymer solution to a nearest downward vertical positioning baffle further comprises one or more baffle extensions. The method of claim 22, wherein the one or more baffle extensions comprise a plurality of rod-like protrusions extending from a bottom edge of one of the baffles, the protrusions transporting the polymer solution to a nearest downward Position the bezel vertically. The method of claim 16, wherein the support structure comprises a housing comprising a first pair of opposite sides and a second pair of opposite sides, wherein the two or more columns of vertically aligned baffle columns are disposed in the first Each baffle between the opposite sides and the plurality of baffles is disposed between the second pair of opposite sides, and wherein the second pair of opposite sides includes a vapor escape adapted to permit release from the polymer solution Multiple openings. The method of claim 24, wherein the plurality of openings adapted to allow vapor exiting from the polymer solution to escape are adjacent to a gap between two adjacent baffles of the plurality of baffles.